Precision CNT Cutting Mechanism
Precision CNT Cutting Mechanism (LAR-TOPS-234)
A cutting mechanism for carbon nanotube yarns, tapes, sheets and polymer composites thereof
NASA Langley Research Center has developed a simple mechanism for the clean cutting of high strength and high toughness carbon nanotube/polymer fiber composites on demand without high blade wear, replacement rates and related high costs. The cutter is comprised of a set of blades both to score through any resin coating the fibers and to provide an electrical current to cut through the fiber/composite reinforcement and any remaining resin in yarns, tapes and sheets. This technology offers the potential of a very meaningful advance in a critical subsystem area (CNT/composite cutting) in a growing industry. Industry experts recognize the issue as extremely important and one with unsatisfactory solutions for much of the industry, in particular for product manufacturers who turn the CNT/composite raw materials into products of many varieties and properties. The initial application of this technology addresses a rapidly growing component of the market — 3D CNT printing, in which the high strength of CNTs, and especially reinforcements such as yarns, tapes and sheets makes them very difficult to cut.
This filament cutting mechanism takes advantage of the electrical conductivity and chemistry of CNT fiber reinforcement to provide a means to achieve clean and precise cuts while utilizing a low amount of energy. The technology employs an opposing set of blades (knives, cursors, or wheels) that serve as both cutter and electrodes, and between which the region of the filament to be cut is isolated. The blades serve to score and degrade any resin coating in the reinforcement fiber, enabling the oppositely dc charged blades to come into contact with the electrically conductive fiber, completing an electrical circuit. This completion of the circuit causes a surge of electrical current to flow through the fiber in the small region between the blades and thus causes the fiber to rapidly heat up. The rapid heating causes the oxidation of any polymer that is on the fiber surface. Additionally, rapid heating also causes ablation/vaporization of the fiber and/or polymer coating. There is no shearing action required to cut the very strong, tough fibers, which eliminates unintended damage to the fibers due to them being dragged by the blade. Increased blade life is thus an additional benefit. A key aspect of the technology is that it is designed as an in-line, embedded technology for applications such as its initial design goal 3D printing.
- Ideal for integration as an in-line embedded cutting subsystem for applications such as 3D printing
- High precision
- Low waste and low cost
- High throughput
- Excellent operational variability
- Takes advantage of the electrical, thermal and chemical properties possessed by CNTs to provide a cutting method that provides multiple fundamental benefits
- Promises to enable use of high quality, high yield of carbon nanotube-based structural materials for use in mission-critical NASA applications
- Enables other in-line/embedded, continuous throughput cutting applications that are naturally expensive and impractical for laser-based and similar high-energy cutting mechanisms of this class of materials